1. Field of the Invention
The present invention relates to a lamp changing system in a liquid crystal display (hereinafter "LCD") projector and more particularly, to a replaceable arc-tube as a light source with a reflective facet attached to a lamp in a front projection type LCD projector
2. Description of the Related Art
Various types of front projection LCD projectors are known in the art. For example, as shown in FIGS. 1 and 2, one such front projection LCD projector, includes first dichroic mirrors 2, 3 and 4 for separating red, green and blue from white light illuminated from a lamp 1, LCDs 5, 6 and 7 for displaying respective image signals of the colors, and condenser lenses 9, 10 and 11 disposed on the light source side of the LCDs 5, 6 and 7. The front projection LCD further includes second dichroic mirrors 12, 13 and 14 for synthesizing the three colors from the LCDs 5, 6 and 7, and a projection lens 8 for projecting the displayed images from the LCDs 5, 6 and 7 onto a screen. As can be seen in FIG. 1, the first dichroic mirrors 2, 3 and 4 are color separation devices and the second dichroic mirrors 12, 13 and 14 are color synthesis devices.
As shown in FIGS. 2A-2C, the lamp 1 as a light source includes reflective facet 1a, an arc-tube 1b as a luminous body, and an electric wire 1c for supplying an electric source. The lamp 1 has a useful life of several thousands hours and its lifetime depends on the arc-tube 1b. Therefore, the lamp 1 has to be replaced when the arc-tube 1b burns out. Further, it is expensive to replace the high priced reflective facet 1a in the lamp 1 and it is difficult to handle the reflective facet 1a manually.